Punching implement



April 19, 193s.

rH. El. wANER PUNCHING IMPLEMENT Filed July ll. 1955 n E27/73E HEE/.FUEUEE Patented Apr. 19, 1938 NHTED STATES PATENT OFFICE PUNCHING lhIPLEMENT Application July 11,1935, -Serial No. 30,890

5 Claims.

This inventionl relates to cutting devices and is especially useful where openings are to be formed in thin walls of articles made oi' metal or other rigid or semi-rigid materials and one side only of the wall is accessible or convenient for support against the cutting force.

It is often necessary to provide non-circular apertures in a thin sheet of metal or other rigid or senil-rigid material where the sheet is a portion of the wall of a closed article readily accessible from one face but inaccessible from the other face, or when the location of the desired aperture is so far from the margin of a sheet as to preclude the use of a punch press or other similar device.

I'he principal objects of the present invention are to provide facility and economy of operation, to provide for cutting without distortion of the surrounding sheet, to'provide for operation from one side only of the sheet, and to accomplish accuracy of cut. i

Other objects will appear from the following description and the accompanying drawing.

Of the drawing:

Fig. 1 is an elevation, partly in section, showing the device in its preferred form as it is inserted through an initial circular aperture in the wall of a tubular body of sheet material, the full lines showing the relative relation of the'handles before cutting and the dot and dash vlines showing the position of one of the handles after the cutting operation is accomplished.

Fig. 2 is a similar view part of the handles being broken away, showing the device at completion of the cut.

Fig. 3 is a detail sectional view taken on line 3-3 of Fig. 1.

Fig. 4 is a view, partly in section, and similar to Figs. 1 and 2, but having the operating mechanism broken away, showing a modied form of the device.

Fig. 5 is a perspective view of a Vtubular sheet metal article showing at I2 a circular initial aperture and at II an aperture which has been enlarged to provide a keyway by use of the device of this invention.

Referring to the drawing, the numeral I0 designates the thin outer wall of a hollow article in which it is desired to form apertures of non-circular shape such as the key-hole shaped aperture II. A circular initial opening I2 is rst drilled through the wall I0 and the device of the present invention is introduced through this initial opening and then operated to remove a part of the wall adjacent the initial opening to provide the keyway Il.

The device used for enlarging the initial opening comprises a die member I4 formed with a keyhole shaped die aperture I5 extending there- Il through. A pilot I6 extends through the aperture in the die Il and is xed to the die by ascrew Il. Pilot I6 is slotted lengthwise to provide a guideway I8 for a draw cutter I9. The draw cutter includes a stem 2li adapted to be rel0 ciprocated through a guide bushing 2l to which the pilot I6 is fixed by a screw 22. The cutter I9, in the form of the device illustrated in Figs.

1 to 3 is preferably integral with the stem 20 and has a single oifset cutter 23 adapted to cooperate l5 with the key aperture I5Rof the die when the cutter is retracted toward the die. The dimensions of the cutter are such that when projected through the die it may be inserted through the metal aperture I2 in the wall I0y as shown in Fig. 1. The clearance space above the cutter 23 then permits the movement of the tool laterally along the wall I0 to a position where the pilot I6 may be pushed through the aperture I2 to bring the face of the die IB in contact with the 25 wall I0. In this position the cutter 23 will underlie the wall I0 and upon retraction of the cutter a slug 24v of material will be sheared from the wall as seen in Fig. 2. An opening 25 through the guide bushing 21| permits the escape of the 30 slug.

As a convenient means for operating the parts just described, a pair of 'operating levers 26 and 21 pivoted at 28 after the manner of pliers may be provided. Lever 26 is fixed to the guide bush- 35 ing 2i and lever 21 is provided with a pin 29 which loosely engages an ear 30 formed on the cutter stem.

In the modified form of the device, illustrated in Fig. 4, the manipulating levers, guide-bushing 40 pilot, and die are the same as in the preferred form ofthe device. The cutter member comprises a plunger'stem 40 having an ear 4I for engaging the pin 29 at its upper end, and a pivot pin 42, at its lower end, to vwhich a swinging cut- 45 ter blade 43v is pivoted. Blade 43 is formed with a cutter 445 projecting forwardly at its lower end and a raised cam surface 45 at the rear of its lower end. In this form of the device the cutter blade is of such dimensions that when ex- 50 tended it does not project laterallygbeyond the pilot I6 and is held against the pilot by a leaf spring 4S, but in its retractive movement the cam surface 45 engages the guide surface of the pilot and causes the cutter 44 to be projected iater- 55 ally as shown by the dot and dash lines in Fig. 4. This modif* :ation enables the device to be inserted without movement laterally with respect to the initial aperture.

In either form of the device a spring 41 attached to the lever 26 normally holds the blade in its projected position.

While the device has been shown as constructed to cut a keyway adjacent the initial aperture, it is apparent that different cutting blades and dies may be used to cut extensions of the initial aperture of different shapes.

In the vuse of the device the metal or other material surrounding the initial opening is held flat against the face of the die and the cutting is accomplished without deformation of the wall around the aperture. The device is especially useful in forming apertures through the thin metal skin of aircraft where anchoring members are to be secured thereto.

I claim:

1. Hand-operated cutting apparatus adapted to enlarge an initial small aperture in sheet metal or other stiff sheet material by operation from one side only of the material, said apparatus comprising a die member adapted to support the material adjacent to the aperture, a reciprocable cutter extending past the die and adapted to pass through the initial aperture, said cutter having a laterally projecting cutting shoulder cooperating with the die to remove a determinate quantity of material in a single retracting movement to produce the desired enlargement and means for supporting and operating the apparatus manually, said means comprising a pair of manually operated arm members one of which is connected with said die and the other of which is connected with said cutter for retracting the same to effect such cutting in cooperation with the die.

2. Cutting apparatus adapted to enlarge an initial small aperture in sheet metal or other stiff sheet material by operation from one side only of the material, said apparatus comprising a die member adapted to support the material adjacent to the aperture, a reciprocable cutter extending past the die and adapted to pass through the initial aperture, said cutter having a laterally projecting cutting shoulder cooperating with the die to remove a determinate quantity of material in a single retracting movement to produce the desired enlargement, means for retracting the cutter to effect the cutting in cooperation with the die, and means additional to said cutter for positively locating the die with respect to the aperture during the cutting movement for removing a determinate quantity of the material.

3. Cutting apparatus adapted to enlarge an initial small aperture in sheet metal or other stiff sheet material, said apparatus comprising a die member adapted to support the material adjacent to the aperture, a pilot member extending past the face of the die and adapted to be positioned in the aperture in the material in contact with the side thereof to locate the die with respect to the aperture, a reciprocable cutter extending past the die and adapted to pass through the aperture along the pilot member, said cutter having a laterally projecting cutting shoulder cooperating with the die to remove a determinate quantity of material in a single retracting movement to produce the desired enlargement, and means for retracting the cutter to effect the cutting in cooperation with the die.

4. Cutting apparatus adapted to enlarge an initial small aperture in sheet metal or other stii sheet material, said apparatus comprising a die member adapted to support the material adjacent to the aperture, a reciprocable cutter extending past the die and having a head adapted to pass through the aperture and a reduced shank, the lateral extension of the head past the shank constituting a cutting shoulder which cooperates with the die to remove a determinate quantity of material in a single retractive movement to produce the desired enlargement, a pilot member extending past the face of the die along a portion only of the reduced shank of the cutter and adapted to be positioned in the aperture in the material in contact with the side thereof to locate the die with respect to the aperture, the pilot member being grooved to accommodate and guide the shank of the cutter, and means for retracting the cutter into cutting engagement with the die.

5. Cutting apparatus adapted to enlarge an initial small aperture in sheet metal or other stiff sheet material, said apparatus comprising a die member adapted to support the material adjacent to the aperture, a reciprocable cutter having a shank and a head including a laterally projecting cutting shoulder cooperating with the die to remove a determinate quantity of material in a single retractive movement to produce the desired enlargement, a pilot member extending past the face of the die and adapted to be positioned in the aperture in the material in contact with the side thereof to locate the die with respect to the aperture, the pilot member being grooved to accommodate the shank of the cutter, the head of the cutter in its extended position being sheltered by the pilot and adapted to pass through the aperture in advance thereof, means for moving the cutter laterally with respect to the pilot into alignment with the die, and means for retracting the cutter to effect the cutting in cooperation with the die.

HARRY E. WANER. 

